Tracking control system using intermittently recorded pilot signals

Abstract

A control signal recording and reproducing system for exactly tracking a record track in a helical scan type VTR or the like is disclosed. Intermittent pilot signals are recorded with the frequency spectra thereof being interleaved between adjacent tracks. In a reproducing operation, the main track pilot signals and the adjacent track pilot signals are separated by a comb type filter, and using a time position of the main pilot signals as a reference, the adjacent track pilot signals are separated in time to the front adjacent track pilot signal and the rear adjacent track pilot signal to detect the direction of a tracking error.

What is claimed is: 
     
       1. A tracking control pilot signal recording and reproducing system for controlling a position of a reproducing means relative to the tracks of a moving recorded medium which it reproduces, comprising: means for supplying a main information signal to be recorded and reproduced;   means for generating two kinds of intermittent pilot signals, the frequency band of each being lower than that of the main information signal, the frequency spectra of said two kinds of intermittent pilot signals being frequency interleaved with each other and sharing almost the same frequency band;   means for recording said main information signal in a plurality of adjacent tracks mixed with one of said intermittent pilot signals on a (2N-1)th recording track and mixed with the other intermittent pilot signal on a 2Nth track, where N is an integer, N=1, 2, 3, . . . , on a recording medium;   means for arranging the recording positions of said intermittent pilot signals on the (2N-1)th track and (2N+1)th track, so they do not align in a direction transverse to the recorded tracks, and for arranging the recording positions of said intermittent pilot signals on the 2Nth track and (2N+2)th track so they do not align in a direction transverse to the recorded tracks;   means for reproducing said recorded signal;   means for separating reproduced pilot signals from the resulting reproduced signal;   means for separating from said reproduced pilot signals, the pilot signal of a main reproduced track and the pilot signals of front and rear adjacent tracks by using a comb filter;   gating means for separating the pilot signal of the front adjacent track from the pilot signal of the rear adjacent track, said gating means being responsive to gate pulses produced from the pilot signal timing of said main reproduced track;   means for comparing the level of the separated pilot signals of said front adjacent track and rear adjacent track; and   means for controlling the position of said reproducing means relative to the tracks of said recording medium using a signal derived from the comparison of the levels of said front and rear adjacent track pilot signals.   
     
     
       2. A system according to claim 1, wherein said means for controlling controls at least one of the position of said reproducing means and the movement speed of said recording medium. 
     
     
       3. A tracking control pilot signal recording and reproducing system for controlling a position of a reproducing means relative to the tracks of a moving recorded medium which it reproduces, comprising: means for supplying a main information signal to be recorded and reproduced;   means for generating two kinds of intermittent pilot signals, the frequency band of each being lower than that of the main information signal, the frequency spectra of said two kinds of intermittent pilot signals being frequency interleaved with each other and sharing almost the same frequency band, one of said intermittent pilot signals having a center frequency of nf H  and its sideband spreading on both sides thereof with spectral components being spaced by an interval of f H  /2, the other intermittent pilot signal having a center frequency of {n+(2m-1)/4} f H   and its sideband spreading on both sides thereof with spectral components being spaced by an interval of f H  /2, where n, m are integers and f H  is a horizontal synchronizing frequency of a television signal;   means for recording said main information signal in a plurality of adjacent tracks mixed with one of said intermittent pilot signals on a (2N-1)th recording track and mixed with the other intermittent pilot signal on a 2Nth track, where N is an integer, N=1, 2, 3, . . . , on a recording medium;   means for arranging the recording positions of said intermittent pilot signals on the (2N-1)th track and (2N+1)th track, so they do not align in a direction transverse to the recorded tracks, and for arranging the recording positions of said intermittent pilot signals on the 2Nth track and (2N+2)th track so they do not align in a direction transverse to the recorded tracks;   means for reproducing said recorded signal;   means for separating reproduced pilot signals from the resulting reproduced signal;   means for separating from said reproduced pilot signals the pilot signal of a main reproduced track and the pilot signals of front and rear adjacent tracks by using a comb filter;   means for separating the pilot signal of the front adjacent track from the pilot signal of the rear adjacent track by gating the front and rear adjacent track pilot signal using a gating pulse produced from the main track pilot signal;   means for comparing the level of the separated pilot signals of said front adjacent track and rear adjacent track; and   means for controlling the position of said reproducing means relative to the tracks of said recording medium using a signal derived from the comparison of the levels of said front and rear adjacent track pilot signals.   
     
     
       4. A system according to claim 3, wherein said means for separating said main reproduced track pilot signals from said adjacent track pilot signals comprises a comb filter having a two-horizontal scanning period delay line. 
     
     
       5. A system according to claim 3, wherein said main information signal is a television signal, and said intermittent pilot signals are generated in every other horizontal scanning period of said television signal. 
     
     
       6. A system according to claim 3, wherein said main information signal is a television signal, and said intermittent pilot signals are generated in every other horizontal blanking period of said television signal. 
     
     
       7. A system according to claim 3, wherein said means for controlling controls at least one of the position of said reproducing means and the movement speed of said recording medium. 
     
     
       8. A signal tracking control system for use with a recording and reproducing apparatus, said system including a recording apparatus comprising: oscillator means for generating an oscillation signal of a frequency substantially equal to nf H , where n is an integer and f H  designates a horizontal sync signal frequency of a video signal;   means for gating the oscillation signal in sync with every other horizontal sync signal (1/2 f H ) of the video signal;   switching means receiving a gated oscillation signal and being responsive at least to a first alternating pilot signal for switching between positions causing non-inversion and inversion of the gated oscillation signal to alternately produce a first tracking control intermittent pilot signal of a first phase and a second tracking control intermittent pilot signal having a phase which alternates between said first phase and an inversion thereof, said first and second intermittent pilot signals being produced in response to every other horizontal sync signal of the video signal, the frequency band of each of said first and second intermittent pilot signals being lower than that of the video signal and the frequency spectra of said first and second intermittent pilot signals being frequency interleaved with each other and sharing almost the same frequency band;   means for recording said video signal mixed with said first pilot signal in a (2N-1)th track and mixed with said second pilot signal in a 2Nth track of said plurality of adjacent tracks where N is an integer, such as N=1, 2, 3, . . . ;   means responsive to said alternating pilot signal for resetting said gating means to arrange the recording positions of the intermittent pilot signals on the (2N-1)th and (2N+1)th tracks so that they do not align in a direction transverse to the tracks, and to arrange the recording positions of the intermittent pilot signal on the 2Nth and (2N+2)th tracks so that they do not align in a direction transverse to the tracks, respectively;   said system including a reproducing apparatus, comprising:   means for reproducing recorded signals from the recording medium;   filter means for deriving a signal mixture of pilot signal components of a main reproduced track and front and rear adjacent reproduced tracks from the reproduced signals;   non-inversion/inversion switching means responsive at least to a second alternating pilot signal, for switching between positions causing non-inversion and inversion of the derived pilot signal components to alternately reproduce the first and the second intermittent pilot signals;   first separation means for separating a pilot signal component of the main reproduced track and pilot signal components of the front and rear adjacent tracks, wherein said separation means comprises a delay means for delaying the pilot signal components from said switching means by a 2H period, where H designates one horizontal scanning period of the video signal, an adder and a subtractor for respectively adding to and subtracting from the pilot signal components from said switching means the delayed pilot signal components to separate out the main reproduced track pilot signal component and the adjacent tracks pilot signal components, respectively;   second and third separation means for substantially separating the pilot signal components of the front and rear adjacent tracks respectively from said adjacent tracks pilot signal components in response to said main reproduced track pilot signal component and the horizontal sync signal;   comparator means for comparing levels of the separated pilot signal components of the front adjacent track and the rear adjacent track; and   means for controlling the position of said reproducing means relative to the tracks of said recording medium using a signal derived from the comparison of the levels of said front and rear adjacent track pilot signals.   
     
     
       9. A system according to claim 8, wherein said means for controlling controls at least one of the position of said reproducing means and the movement speed of said recording medium. 
     
     
       10. A signal tracking control system for use with a recording and reproducing apparatus, said system including a recording apparatus comprising: oscillator means for generating a first oscillation signal of a frequency substantially equal to nf H , and second oscillator means for generating a second oscillation signal of a frequency substantially equal to {n+(2m31 1)/4} f H , where n, m are integers and f H  designates a horizontal sync signal frequency of a video signal;   gating means;   switching means responsive to a first alternating pilot signal for alternately connecting the first and the second oscillation signals to said gating means for gating to the output of said gating means, the connected oscillation signal in every other horizontal scanning period of the video signal and to thereby alternately produce a first tracking control intermittent pilot signal of a first phase and a second tracking control intermittent pilot signal having a phase which alternates between said first phase and an inversion thereof, wherein the frequency band of each pilot signal is lower than that of the video signal and the frequency spectra of said first and second intermittent pilot signals is frequency interleaved with each other and shares almost the same frequency band;   means for recording said video signal mixed with said first pilot signal in a (2N-1)th track and mixed with said second pilot signal in a 2Nth track of said plurality of adjacent tracks where N is an integer, such as N=1, 2, 3, . . . ;   means responsive to said pilot signal alternating signal for resetting said gating means to arrange the recording positions of the pilot signals on the (2N-1)th and (2N+1)th tracks so that they do not align in a direction transverse to the tracks, and to arrange the recording positions of the pilot signal on the 2Nth and (2N+2)th tracks so that they do not align in a direction transverse to the tracks, respectively;   said system including a reproducing apparatus, comprising:   means for reproducing recorded signals from the recording medium;   filter means for deriving a signal mixture of pilot signal components of a main reproduced track and front and rear adjacent reproduced tracks from the reproduced signals;   
     
     
       non-inversion/inversion switching means responsive at least to a second alternating pilot signal, for switching between positions causing non-inversion and inversion of the derived pilot signal components to alternately reproduce the first and the second intermittent pilot signals; first separation means for separating a pilot signal component of the main reproduced track and pilot signal components of the front and rear adjacent tracks, wherein said separation means comprises a delay means for delaying the pilot signal components from said switching means by a 2H period, where H designates one horizontal scanning period of the video signal, an adder and a subtractor for respectively adding to and subtracting from the pilot signal components from said switching means the delayed pilot signal components to separate out the main reproduced track pilot signal component and the adjacent tracks pilot signal components, respectively;   second and third separation means for substantially separating the pilot signal components of the front and rear adjacent tracks respectively from said adjacent tracks pilot signal components in response to said main reproduced track pilot signal component and the horizontal sync signal;   comparator means for comparing levels of the separated pilot signal components of the front adjacent track and the rear adjacent track; and   means for controlling the position of said reproducing means relative to the tracks of said recording medium using a signal derived from the comparison of the levels of said front and rear adjacent track pilot signals.   
     
     
       11. A system according to claim 10, wherein said means for controlling controls at least one of the position of said reproducing means and the movement speed of aaid recording medium. 
     
     
       12. A signal tracking control system for use with an apparatus for sequentially recording and reproducing a video signal in a plurality of adjacent tracks on a recording medium, said system including on the recording side: first means for generating for every 2H period, where H designates a horizontal scanning period of the video signal, a first burst-type pilot signal having a center frequency of substantially nf H , where n designates a positive integer and f H  a horizontal sync frequency of the video signal;   second means for generating for every 2H period a second burst-type pilot signal having as a center frequency one of (n+1/4)f H  and (n-1/4)f H , said second burst-type pilot signal having a phase which is inverted every 2H period;   third means for sequentially recording with the video signal the generated first pilot signals and the generated second pilot signals alternately and respectively on one and the other of (2k-1)th and (2k)th tracks of said adjacent tracks, where k designates an integer, e.g., k=1, 2, 3, . . . , with the pilot signals of adjacent tracks being frequency interleaved to make the first and second burst-type pilot signals share a sideband region;   fourth means for controlling the generation of said first and second burst-type pilot signals to locate the recorded positions of the burst-type pilot signals on the (2k-1)th and (2k+1)th tracks, so that they do not align in a direction transverse to the tracks and to locate the recorded positions of pilot signals on 2kth and (2k+2)th tracks, so they do not align in a direction transverse to the tracks;   said system including on the reproducing side:   fifth means for reproducing a mixed signal composed of the recorded video signal and pilot signals of a main reproduced track, and front and rear adjacent reproduced tracks;   sixth means for extracting pilot signal components from the reproduced mixed signal;   seventh means for separating pilot signal components of the main reproduced track, and adjacent reproduced tracks respectively, said seventh means means comprising a two horizontal scan period delay line for delaying the derived pilot signal components by a 2H period, an adder for adding the derived signal components and the delayed signal components to separate the main reproduced track pilot signal component, and a subtractor for subtracting one from the other of said derived and said delayed signal components to separate the adjacent tracks pilot signal components;   eighth means for detecting a reproduction timing of the separated main reproduced track pilot signal component and substantially separating in time the front adjacent track pilot signal component and the rear adjacent track pilot signal component with reference to the detected reproduction timing;   ninth means for comparing levels of the separated front and rear adjacent track pilot signal components to produce a tracking error signal; and   tenth means for controlling the position of said reproducing means relative to the tracks of said recording medium in response to said tracking error signal.   
     
     
       13. A system according to claim 12, wherein said means for controlling controls at least one of the position of said reproducing means and the movement speed of said recording medium.